QuakeScout
Magnitude2.7

Reviewed by USGSAlaska11y ago

M2.7 earthquake in Fox Islands, Aleutian Islands, Alaska

Tuesday, September 22, 2015, 03:44:26 UTC · 52.262°N, 170.278°W

A magnitude 2.7 earthquake struck in Fox Islands, Aleutian Islands, Alaska on Tuesday, September 22, 2015, 03:44:26 UTC, at a depth of 32.0 km (shallow).

Magnitude
2.7
Minor · ml
Depth
32 km
Shallow
Felt reports
0
Max intensity I
Est. shaking
—
No ShakeMap
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 50 km aftershock search area

In context

How big was it, and why here?

Energy released

169 kg of TNT

That is about 1/88,990 of the Hiroshima bomb. A magnitude 5.0 releases about 2,818 times more energy.

Tectonic setting

87 km

from the nearest mapped plate boundary, between the North American and Pacific plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.

Depth: shallow

32 km

Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.

Did You Feel It?

Where it was felt

No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.

I felt it — report to USGS ↗

USGS PAGER estimate

Who was exposed to shaking

USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.

After the main event

Aftershocks within 50 km

USGS lists 5 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M3.5 on October 20, 2015. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M31h6h1d3d7d14d30dMainshock M2.7
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 3.580 km SW of Nikolski, Alaska11y ago · 47 km E of this epicenter
  2. 2.574 km WSW of Nikolski, Alaska11y ago · 48 km NE of this epicenter
  3. 2.7141 km SW of Nikolski, Alaska11y ago · 21 km SW of this epicenter
  4. 2.680 km SW of Nikolski, Alaska11y ago · 45 km E of this epicenter
  5. 2.7159 km SW of Nikolski, Alaska11y ago · 39 km W of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 726 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.8234 km SSW of Nikolski, AlaskaMarch 7, 1929 · 155 km S of this epicenter
  2. 7.881 km E of Nikolski, AlaskaJuly 2, 1965 · 196 km NE of this epicenter
  3. 7.4133 km WNW of Nikolski, AlaskaApril 18, 1916 · 134 km N of this epicenter
  4. 7.3Fox Islands, Aleutian Islands, AlaskaJune 24, 2011 · 109 km W of this epicenter
  5. 7.135 km SW of Nikolski, AlaskaMarch 11, 1957 · 88 km NE of this epicenter
  6. 6.980 km SW of Nikolski, AlaskaMarch 9, 1957 · 51 km E of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 14 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:

  1. 1901M7.8

    Aleutian Islands: Fox Islands

    31 Dec 1901 · 104 km away

    Limited damage (under $1M)tsunami

  2. 1965M6.5

    Aleutian Islands: Fox Islands

    2 Jul 1965 · 203 km away

    Limited damage (under $1M)tsunami

  3. 1917M7.9

    Alaska Peninsula

    31 May 1917 · 291 km away · intensity V

  4. 1902M7.8

    Aleutian Islands: Fox Islands

    1 Jan 1902 · 189 km away

  5. 1907M7.8

    Aleutian Islands

    2 Sep 1907 · 52 km away

  6. 1929M7.8

    Aleutian Islands: Fox Islands

    7 Mar 1929 · 142 km away · intensity V

    tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

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